1. Field of the Invention
This invention relates to an optical reading apparatus and/or an optical writing apparatus, and more particularly to a circuit board for an optical element for use with an optical printer.
2. Description of the Related Art
In recent years, employment of electronic technique spreads over a variety of fields from business machines to household furnishings, toys and so forth. Consequently, reduction in size and weight, increase in processing speed and improvement in accuracy and so forth proceed in various fields.
Particularly, in recent years, requirement for realization of simplicity, compactness and reduction in cost together with a high quality, a high gradation and a high resolution has been and is increasing in various image inputting terminal equipments beginning with a high speed facsimile, a small size scanner and a copying machine of the white board type as well as copying machines as represented by electronic photographs. Further, it has been examined by the inventors of the present invention to position, in order to achieve reduction of the output of a light source upon reading of an original, a reading semiconductor element and the original as near as possible.
In particular, an investigation has been made for a glass substrate or a plastic film of a very small thickness of 0.1 mm or less as a transparent base member for a circuit board on which semiconductor elements (of the type having pads made of gold or aluminum as terminals for connection to an external circuit board or of the bear chip type) can be mounted.
It is estimated that high integration and reduction in size and weight of electronic appliances will further proceed in the future. Even at present, flexible circuit boards which include a plastic film or a plastic sheet as a base member are used widely particularly to extremely bent portions or to those portions for which reduction in weight is desired.
The plastics have flexibility, and electrodes can be formed on the plastics readily by sputtering or vacuum vapor deposition. The plastics are superior also in productivity. However, the plastics are dielectrics and are liable to generate and be charged with static electricity by friction. The inventors of the present invention have found out that the charge has such an influence on semiconductor elements mounted on a circuit board formed from a base member of a plastic film or a like material that the output signals of the semiconductor elements suffer from an error or disturbance, resulting in noise of signals in the apparatus to cause a malfunction of the apparatus.
Further, in an optical reading apparatus, an original, which moves below a transparent circuit board in the form of a film, is illuminated by light emitted from a light source and transmitted through the circuit board to read the original, and in this instance, light from the light source is reflected by multipath reflection between the original and the circuit board. The inventors of the present invention have found out also that, since a reading light receiving element receives the light after multipath reflection, a disturbance occurs with the output signal of the light receiving element, and consequently, precise reading is not achieved.